Automatic mandrel checker

Abstract

Apparatus for sensing contaminant material or hung-up work pieces on mandrels, such as the core rods of injection blow molding machines, consists of a sensing member adapted to be moved through a programmed path corresponding to the bottom contour edge of the mandrel and to give an output responsive signal when any material or work piece remains on the mandrel and interrupts the programmed movement of the sensing member. Generally, one or more horizontally extending mandrels are checked by a sensing member linked through a connecting member with a cam following a cam track corresponding in shape and located below the bottom contour edge of the mandrel to be checked. In the preferred form of the invention, an injection blow molding machine includes an automatic stripper and checker, in which stripping fingers associated with the connecting member precede the sensing member and thus strip a preformed work piece off the mandrel simultaneously with the checker sensing member movement along the mandrel length. Preferably, the sensing member consists of a horizontally disposed rod adapted to travel along either one or a plurality of parallel core rods with the sensing member forming part of an electrical circuit. Upon engagement of the sensing member with hung-up material or work piece, the sensing member is adapted to yield downwardly and thereby to open the circuit and provide a responsive output signal.

Having described my invention, I desire to claim and secure by letters patent, the following: 
     
       1. Automatic mandrel checker adapted to indicate the presence of foreign material on a generally horizontally extending mandrel having a non-linear profile, said checker consisting of a sensing member urged upwardly to a vertical position along a line corresponding to the bottom edge of the mandrel which said checker is adapted to check, and a sensor member moving means for moving said sensor member generally horizontally and for displacing said sensor member vertically, the resultant path of movement of said sensor member corresponding to the bottom edge contour of said mandrel and means responsive to any interference with said sensor member movement to indicate the presence on said mandrel of foreign material. 
     
     
       2. Automatic mandrel checker, as recited in claim 1, wherein said sensor member moving means comprises a cam track which corresponds in shape to the bottom edge contour of said mandrel and is disposed below and parallel thereto, a cam member on said cam track, a connecting member to which is attached said cam member and said sensing member, said sensing member mounting permitting said member to yield downwardly, said responsive means being adapted to respond to said downward yielding movement, and said connecting member being connected to a horizontal driving means. 
     
     
       3. Automatic mandrel checker, as recited in claim 2, wherein the mandrel which said checker is adapted to check is one of a plurality of identical such mandrels extending parallel to one another in a horizontal plane, and said sensor member comprises a rod adapted simultaneously to check the bottom edges of all of said mandrels at corresponding points thereon, said rod being attached to said connecting member at spaced points along the length of said rod, said connecting member attached to a cam, in turn riding on said cam track. 
     
     
       4. Automatic mandrel checker, as recited in claim 3, wherein said connecting means is connected to said horizontal driving means through pivotally mounted parallelogram links. 
     
     
       5. Automatic mandrel checker, as recited in claim 4 wherein said sensing member rod forms part of an electrical circuit when said member is in its upwardly urged, non-yielded position, which circuit is open upon downward yielding movement of said member relative to said connecting member. 
     
     
       6. In an injection blow molding machine having a work stripping station at which an injection blow molded product mounted on a mandrel is stripped therefrom, an automatic mandrel checker, as recited in any one of claims 2, 3, 4, or 5, said checker disposed at said work stripping station and adapted to strip said product from said mandrel at said station, said connecting member of said checker being connected to stripping fingers adapted to traverse said mandrel ahead of said sensing member in the course of said horizontal movement thereof and thereby to strip a work piece formed thereon. 
     
     
       7. An injection blow molding machine having a work stripping station at which an injection blow molded product mounted on a mandrel is stripped therefrom and having an automatic mandrel stripper and checker as recited in claim 5 disposed at said work stripping station and adapted to strip said product from said mandrel at said station, wherein said electrical circuit is formed by contacts with said sensing member rod at the opposite ends thereof.